Influence of Humidity and Atmospheres Without O2 or CO2, on Formation of Calcium Oxalate Crystals in Three Legume Taxa

High relative humidity greatly reduces transpiration and causes a pronounced decrease in crystal formation in Phaseolus, but not in Canavalia and Rhynchosia. Variation in calcium concentration of the nutrient solution does not alter these results. An atmosphere without oxygen has no significant influence on crystal development, nor has an atmosphere without CO2. These results suggest that oxalate biosynthesis in C3 legumes may not be directly associated with photorespiration and photosynthesis. Likewise, there appears to be no simple relationship between transpiration rate and calcium oxalate crystal production. Further work is warranted in order to expand upon these findings.